Studies of the minor products of anti-benzo(a)pyrene diolepoxide-DNA reaction will be completed by attempts to identify the anticipated N3-adenine derivative. The synthesis and study of the DNA reaction of the diolepoxide of DMBA will be attempted. The generality of the property of tumor promoters to inhibit metabolic cooperation will be tested using a number of different cell types in culture. The molecular basis of mutation induction by carcinogens will be sought by a study of the properties of azaguanine resistant mutants of V79 cells. Using the overcoming of senescence (SEN minus) and anchorage independent growth (AGAR plus) as criteria of transformation of Syrian hamster cells, experiments will be aimed at determining the role of mutation in each of these independent stages of transformation. Methods of gene transfer by DNA-transfection will be used to demonstrate the existence and study the properties of genes controlling malignancy.